When it comes to pitching the best thing that a pitcher can do is get a batter to swing and miss. Pitchers can be successful without being high strikeout pitchers, but generally speaking, the best pitchers throughout history have been the ones that missed more bats than the rest of the league did. Here’s the Top 10 list for the 2015 season for swinging strike rate (swinging strikes / pitches):

Name Swinging Strike %
Clayton Kershaw 15.90%
Max Scherzer 15.30%
Chris Sale 14.60%
Francisco Liriano 14.30%
Carlos Carrasco 14.00%
Cole Hamels 13.30%
Corey Kluber 12.90%
Chris Archer 12.80%
Jacob deGrom 12.70%

Not a bad list to be on.

A few years ago we did not have access to this kind of data for minor leaguers. However in the last few seasons we’ve gone from having it for just Triple-A players to seeing it trickle down to the non-complex level rookie leagues in 2016.

Let’s start with the Billings Mustangs starters. They’ve made it through the rotation one time, so the sample size is incredibly small. It, however isn’t meaningless as we can at least tell how on that given night, their stuff was. Here’s how each of the five starters stacked up in terms of their swinging strike rate:

Pitcher Swinging Strike %
Tony Santillan 19.7%
Adrian Rodriguez 7.1%
Moises Nova 14.8%
Andrew Jordan 16.7%
Jordan Ramsey 4.1%

Tony Santillan was absolutely dominant in his lone start of the season as he racked up a swinging strike rate of 19.7%. One out of five pitches that he threw saw a batter swing and miss. That’s incredibly impressive. Andrew Jordan’s 16.7% in his start was also highly impressive.

What about the full season starters? I’ve gathered the data for those guys. We’ve got their total swinging strike rate for the season, as well as their top swinging strike performance of the season.

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Pitcher Top SwStr% Game
Tot SwStr%
Amir Garrett 20.4% 13.7%
Keyvius Sampson 16.8% 11.8%
Jose Lopez 16.9% 11.6%
Robert Stephenson 18.8% 11.5%
Tanner Rainey 16.8% 11.4%
Cody Reed 16.7% 11.2%
Keury Mella 17.5% 10.6%
Nick Travieso 15.4% 10.2%
Ty Boyles 16.5% 9.7%
Sal Romano 14.1% 9.6%
Seth Varner 15.4% 9.5%
Jacob Constante 16.5% 9.3%
Tejay Antone 13.9% 9.2%
Jackson Stephens 19.0% 9.0%
Tyler Mahle 13.3% 8.9%
Austin Orewiler 11.7% 7.6%
Rookie Davis 15.9% 6.5%

The name at the top is probably one you would expect. Amir Garrett has dominated this season and he’s got some of the better stuff in the entire system. Keyvius Sampson being second is a bit surprising, as is Jose Lopez. While both guys certainly have stuff, neither is considered to have dominant stuff.

Robert Stephenson, in my mind, has the best pure stuff of any starter in the system and I still think it’s not close. That he’s 5th on the list isn’t a surprise. His 11.5% swinging strike rate doesn’t jump off of the list, but part of that could be simply due to the fact that he’s not always throwing a ton of strikes. Tanner Rainey, like Stephenson, isn’t always pounding the strikezone, but when he’s in the zone he’s been able to miss a ton of bats. His fastball is overpowering Midwest League hitters.

Perhaps the most surprising guy from the list is Cody Reed. He’s a guy who pounds the strikezone and has plenty of stuff, but he finds himself 7th on the list. The other big surprise on the list is Tyler Mahle being near the bottom. He’s arguably the top control pitcher in the entire system among the starting pitchers, and he’s 3rd in the system in overall strikeouts. Guys don’t swing and miss often against him, but they seem to be looking at plenty of strikes.

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